Method and device for treating a fiber mass

ABSTRACT

The invention relates to a method and a device for treating a fibre mass, such as for example a nonwoven or a woven. Such fibre masses are conveyed through a pressing mill for treatment where they are pressed in at least one pressing zone by means of a press-roll. By the pressing, a treatment fluid already present in the fibre mass is pressed out of the fibre mass. After the pressing out of the treatment fluid, a second treatment fluid is introduced into the fibre mass. In order to achieve a distribution of the second treatment fluid in the pressed fibre mass as quickly and homogenously as possible, according to the invention it is provided that the treatment fluid is introduced through the pressing surface area into the fibre mass in an expansion region, where the pressing power exerted by the press-roll is reduced in the moving direction of the fibre mass. Here, the pressing surface area is the surface through which the pressing power acts on the fibre mass.

The invention relates to a method for treating a fibre mass, such as awoven cloth or a nonwoven, where the fibre mass is conveyed through apressing mill, where the fibre mass is pressed in at least one pressingzone by the pressing surface area of at least one press-roll by means ofa pressing power acting on the fibre mass, and the pressed fibre mass isimpregnated with a treatment fluid, the fibre mass being passed throughan expansion region in the pressing zone where the pressing power isreduced in the passing direction of the fibre mass.

The invention further relates to a press-roll arrangement for treating afibre mass moving relatively to the press-roll arrangement, comprising apress-roll with a pressing surface area by means of which in operationin a pressing zone a pressing power acting on the fibre mass isgenerated, and with an impregnation means by which in operation atreatment fluid is supplied to the fibre mass, the pressing zone formingan expansion region in operation in which the pressing power is reducedin the moving direction of the fibre mass.

The term pressing surface area designates the surface which limits, asan imaginary or actually existing surface area, the pressing zone fromthe upper or lower side of the fibre mass, i.e. the idealized envelopingsurface via which the pressing power acts on the fibre mass.

For preparing the fibre masses concerned by the invention,conventionally a polymeric mass is melted or dissolved in a solvent andsubsequently drawn over spinning devices to form filament yarns. Forpreparing the filament yarns, various spinning processes, such as dryspinning and wet spinning methods or a combination of dry and wetspinning methods, are possible. In the process, the filaments aregenerated in a spinning machine and drawn off from the same by one ormore draw-off elements being at the same time formed to filament bundlesor tows. Subsequently, the filaments are washed and aftertreated infurther processing steps.

Before the aftertreatment, for example, in the manufacture of staplefibres, the tow of filament yarns arranged in parallel which is drawnoff from the spinning machine is supplied to a cutting device. Afterexiting the cutting device, in general a nonwoven is formed from theindividual staple fibres and deposited on a transport device to befurther treated.

The staples are generated by staple cutting machines, for example in adry cut by the machine described in “Ullman Volume 11,Fasern-Herstellungsverfahren”, pages 249-289.

Viscose fibres are spun in general in aqueous media as cellulosicregenerated fibres. For the staple fibre generation from thecontinuously spun fibre tow, for example a cutting machine is suitablewhich essentially consists of a pair of rolls for feeding the spinningtow to the cutting apparatus, the actual cutting apparatus and a staplefibre washing-down device. The cutting apparatus draws the tow fed bythe draw-off element by means of a water jet injector to thehorizontally rotating cutting knives. The cutting knives maintain theiredge retention during the cutting process by a continuous regrinding.Moreover, by the water jet supply, a first dissolution of the staplefibre stacks formed during the cutting process is effected before thesuspension of the staple fibre stacks at the aftertreatment machine.Such a machine is for example manufactured by the company Ing. A. MaurerS. A.

The aftertreatment of for example viscose fibres can or must be effectedby various treatment steps. In the process, in aftertreatment machinesfor viscose fibres, typically the following treatment steps are carriedout while supplying a treatment fluid: deacidification,desulphurization, washing, bleaching and washing, antichlorinetreatment, washing with water as well as applying an avivage or a fatcoat. These treatment steps are conventionally carried out in a deviceto which the cut staple fibre, also designated as “flock”, comes fromthe cutting machine via a washing-in device while forming a nonwovencoat distributed as uniformly as possible.

The device for treating the fibre mass is conventionally formed as along aggregate in which the fibre mass distributed to a uniform nonwovenor the fibre mass, respectively, is conveyed on a transport meansthrough the individual treatment zones. As a transport means, a beltconveyor, for example with an endless travelling screen or an endlesswire-cloth belt, an oscillating conveyor or an eccentric notchedconveyor can be used.

In the treatment of the fibre mass, care has to be taken that thetreatment fluids supplied in the individual treatment steps are quicklyand homogenously distributed in the suspended nonwoven.

At the same time, it is advantageous to remove the treatment fluid fromthe previous treatment step as completely as possible from the fibremass before carrying out a treatment step.

For removing a treatment fluid from the fibre mass, conventionally apress-roll arrangement is used which exerts a pressing power on thefibre mass. By means of the pressing power, the treatment fluid ispressed out of the fibre mass. In the subsequent treatment step, thepressed fibre mass is then impregnated with the treatment fluidassociated to this treatment step. That is, by means of the press-rollarrangement, two subsequent treatment steps are separated.

In the region where the pressing power acts on the fibre mass, i.e. thepressing zone, shortly after the point of the highest pressing power, aregion is formed where the pressing power is reduced in the conveyingdirection of the fibre mass. This region is designated as expansionregion.

In order to moisten the fibre mass with the treatment fluid,conventionally the fibre mass is passed below spray tubs on a transportdevice. Directly after the pressing out, the treatment fluid is drippedonto the fibre mass by spray installations positioned thereabove.However, the application of the treatment fluid by dropping only effectsa nonuniform impregnation and moistening of the fibre mass just pressed.

A special problem arises in the preparation of cellulose fibres ornonwovens of cellulose fibres which are prepared by an NMMO or lyocellprocess. In the process, a spinning solution containing water, celluloseand tertiary amine oxide is extruded to a filament yarn and drawn.

During the drawing, the cellulose filaments are exposed to a highmechanical stress. The filaments and staple fibres prepared according tothe NMMO or lyocell process comprise a high crystallinity or orientationof the cellulosic molecules, respectively. Due to these product featurescaused by the manufacturing process, lyocell fibres tend to befibrillary. Fibrillation means that due to the high crystallinity andorientation small fibrils split off the circular fibre surface of anindividual fibre. The formation of fibrils continues along the fibreaxis.

In order to reduce the tendency of fibrillation, the fibre can betreated with chemical cross-linkers which bind the fibrillary elementsto the fibre main body. In general, an interlacing or cross-linkageprocess is controlled such that the cellulosic fibre tow is impregnatedwith a chemical cross-linking agent and the cross-linking reaction isstarted by vaporization at elevated temperatures.

The cross-linking agents have to be homogenously introduced into thefibre mass after the fibre preparation, the temperature of the fibreoptionally has to be controlled and washed out of the fibre insubsequent treatment steps. Moreover, the cellulose fibre has to bebrightened and dried, as other non-cellulosic fibres as well.

In this treatment, it is problematic that the cross-linking agents tendto spontaneous chemical degradation or hydrolysis reactions as thechemicals hydrolise in an aqueous medium or are not stable for a longtime, respectively. If the reaction parameters—for example the reactionrate or the reaction temperature—are not exactly observed, degradationor decomposition reactions can also occur. Therefore, the cross-linkingagent has to be introduced in closed regions while controlling thereaction course as exactly as possible. Usually, the cross-linkingagents require a quick introduction into the cellulose fibre with asubsequent quick control of the temperature as well as subsequently awashing out of the remaining chemicals as fast as possible with acooling-down at the same time. During the so-called cross-linkage,elevated temperatures as well as alkaline or acid liquids act on thefibre mass. The chemical reaction of the cellulose with thecross-linking agent is effected at elevated pH-values (for exampleapprox. 11-14), resulting in a hydrolysis of the cross-linking agent.The cross-linking agent's tendency of decomposition can be repressed bythe temperatures in the cross-linking bath being as low as possible. Thelow temperatures can be adjusted in or in front of the pressing device.After the thermal fixation of the cross-linking agent, i.e. the reactionof the cross-linking agent with the cellulose chains between approx. 20and 98° C., the alkali has to be removed from the fibre mass forreducing the strain on the cellulosic fibre.

Due to the high fibre density and fibre swelling in cellulosic fibremasses, moreover long dwell times for penetrating the fibre mass arenecessary, as only a low geodetic height of the liquid positionedthereabove acts on the nonwoven and the pressure losses of the nonwovencan only be overcome by a long action duration of the fluid.

The conventional method and the conventional device, where the pressedfibre mass is only sprayed with a treatment fluid, are not sufficientfor a precise control of the process parameters exactly in treatmentfluids which chemically react easily or decompose, such as cross-linkingagents.

In view of the methods and devices conventionally employed for treatingfibre masses, it is therefore an object of the invention to improve themethod mentioned in the beginning and the device mentioned in thebeginning, respectively, in such a way that a distribution of thetreatment fluid, the temperature-controlling agent (hot water, hotvapour and optionally other heat transfer media) as well as variouswashing media in the fibre mass as fast and homogenously as possible andthus also an exact process control are possible.

This object is achieved for the inventive method mentioned in thebeginning in that the treatment fluid is passed into the fibre mass inthe expansion region through the pressing surface area.

In the press-roll arrangement mentioned in the beginning, this object isachieved in that the press-roll arrangement comprises openings in theexpansion region through which in operation the treatment fluid ispassed through the pressing surface area into the fibre mass.

This solution is simple and has the advantage that the treatment fluidvery quickly and homogenously distributes in the pressed and compressedfibre mass which relaxes in the expansion region. As in the expansionregion the pressing power is reduced in the moving direction of thefibre mass, in this region the fibre mass automatically takes in thetreatment fluid through the pressing surface area. Thus, a uniform andquick penetration of the pressed fibre mass with the treatment fluidalready takes place in the pressing zone. Thereby, the treatment processis easier to control.

The solution according to the invention has the further advantage thatthe overall length of a treatment machine can be essentially reduced. Incontrast to the conventional machines, where due to the spraying apenetration of the fibre mass is only possible by means of a long actiontime and a correspondingly longer conveying distance of the fibre massthrough the treatment zone, with the solution according to the inventiondue to the immediate penetration the next treatment step can directlyfollow the impregnation of the fibre mass with the treatment fluid.

That is, with the solution according to the invention, it is possible todesign the pressing mill similarly to a rolling mill where theindividual rolls directly follow one another in the direction ofrolling. According to a further development of the invention,accordingly in the treatment of the fibre mass several treatment stepscan be carried out successively by passing the fibre mass successivelythrough several press-roll arrangements, in one press-roll arrangementeach a first treatment fluid being pressed out of the fibre mass in thecompression zone and the fibre mass being impregnated with a secondtreatment fluid in the expansion zone.

The fibre mass can be conveyed through the pressing zone by means of aseparate conveying means, for example in the form of a conveyor belt,the press-roll passively rotating along. However, the press-roll canalso be provided with an own driving means. In this case, one candispense with a separate conveying means, as the press-roll itself formsthe conveying means. The peripheral speeds of the press-rolls can bebetween 0.1 and 400 m/min, preferably between 0.1 and 60 m/min, inparticular between 0.1 and 10 m/min. With these peripheral speeds, in atreatment zone a fibre throughput of 10 to 1500 kg/(m²h), preferablybetween 10 and 1200 kg/(m²h), can be achieved. The fibre throughput iscalculated from the weight of the fibre mass in an absolutly drycondition divided by the dwell time per treatment field and isindependent of the length of the treatment field.

In front of the expansion region, the fibre mass can be passed in thepressing zone through a compression region where the pressing power isincreased in the conveying direction of the fibre mass, so that atreatment fluid already present in the fibre mass is pressed out. In afurther advantageous embodiment, in the compression region the pressedout treatment fluid can be let off from the fibre mass through thepressing surface area. For doing so, for example a suction means can beprovided through which in operation the treatment fluid is sucked offfrom the compression region. Instead of a suction means, however, onlyopenings in the pressing surface area can be provided through which thetreatment fluid automatically passes due to the pressing powerincreasing in the treatment direction in the compression region, so thatafter the passage of the fibre mass through the pressing zone almost nomore treatment fluid from the previous treatment step is contained inthe fibre mass.

The line pressure with which a press-roll according to the invention ispressed into the fibre mass is up to 100 N per mm of the roll width.

As a supplement or alternatively to the letting off or sucking off ofthe treatment fluid in the compression zone, a treatment fluid can alsobe passed in the compression zone through the pressing surface area intothe fibre mass for rinsing the fibre mass before pressing it. Forexample, the fibre mass can be rinsed with the treatment fluid suppliedto the upstream press-roll in the expansion zone, so that no treatmentfluid from the treatment step which is arranged by the device in frontof the compression zone in the transport or conveying direction of thefibre mass, can be carried into the treatment step which is arrangedbehind the expansion zone in the conveying direction.

A thorough and uniform impregnation of the fibre mass with the treatmentfluid can be achieved if according to a further advantageous embodimentthe treatment fluid is pressed into the fibre mass under pressure, forexample by nozzles arranged in the pressing region in the compressionand/or expansion region. The liquid throughput referring to thepress-roll width can be between 0.1 and 125 m³/(h m), preferably between0.1 and 50 m³/(h m), in particular between 0.1 and 20 m³/(h m).

A particularly compact construction can be achieved if the impregnationmeans through which the treatment fluid is supplied to the fibre mass isarranged at least by sections within the press-roll. In this case,according to a further embodiment of the invention, the treatment fluidcan be conveyed from the inside of the press-roll through openings intothe fibre mass. For doing so, the press-roll can be provided withopenings at its surface facing the fibre mass through which openings thetreatment fluid is conveyed into the fibre mass. The openings can beformed in the surface of the press-roll regularly or irregularly and forexample comprise a cross-section which is essentially nozzle-like. Theopening degree of the roll, i.e. the relation of the surfaces occupiedby the openings to the overall surface of the roll, can be between 1 and95%, preferably between 3 and 90%, particularly preferred between 3 and85%.

According to another embodiment, the press-roll can, however, form ribsat its surface facing the fibre mass, which form at least by sectionsthe pressing surface area and between which in operation the treatmentfluid can be introduced into the fibre mass. According to furtherembodiments, these ribs can extend essentially transverse to oressentially in the moving direction of the fibre mass.

In order to avoid a carrying away or mixing of the treatment fluids fromthe two treatment steps separated by the press-roll arrangement,according to a further advantageous embodiment, the ribs can be designedas a weir which acts against a flow of the treatment fluid through thepress-roll from the compression region to the expansion zone and thusacts against a carrying away of the treatment fluid. This is inparticular possible if the ribs extend transversely to the movingdirection of the fibre mass. To this end, the height of the ribs can bedimensioned such that in the pressing zone an upper end of a rib facingaway from the fibre mass projects essentially between the compressionregion and the expansion region always above the level of the treatmentfluid in the compression region and/or expansion region.

In particular in the embodiment of the press-roll with ribs being spacedapart and preferably extending transversely to the conveying directionof the fibre mass, spray nozzles can be integrated inside the press-rollaccording to a further advantageous embodiment, through which thetreatment fluid is directed in operation onto the fibre mass preferablyin the pressing zone in a spray or jet form. In order to avoid aconveyance of the treatment fluid out of the compression region throughthe rotating press-roll into the expansion region, the nozzles can alsobe directed to the compression region in order to dilute or displace thetreatment fluid present therein. A complete moistening of the fibre massby the treatment fluid delivered by the spray nozzles is achieved if theatomizing cone of the nozzles essentially overlaps in the region of thefibre mass or in the pressing zone, respectively.

Depending on the type of the treatment fluid used, the size and weightof the fibre mass as well as the composition of the fibre mass, it canbe necessary to regulate the region via which the treatment fluid isconducted through the pressing surface area onto the fibre mass. Fordoing so, the impregnation means can comprise a regulation means bywhich the size and the orientation of the exiting region of thetreatment fluid in the pressing surface area is regulated. To this end,according to a further advantageous embodiment, the regulation means canbe designed as a cover body arranged in the press-roll with a slotarranged in the press-roll, which covers that part of the pressingsurface area or the press-roll through which no treatment fluid is topass. This cover body can for example be designed as a tubular bodyprovided with a longitudinal slot and rotatably held in the press-roll.

Instead of or in addition to a supply line of the treatment fluid fromthe inside of the press-roll, the impregnation means can comprise asupply line through which in operation the treatment fluid is conveyedfrom outside the press-roll essentially into the expansion region. Thissupply line can be arranged according to a further advantageousembodiment at least in the pressing zone at least by sections betweentwo ribs essentially extending in the moving direction of the fibremass. In this case, it is advantageous if the section of the supply linefacing the pressing surface area essentially flushes with the ribs, sothat the pressing surface area is as smooth as possible and offers onlylittle frictional resistance with respect to the fibre mass.

Finally, the invention also relates to a pressing mill for treatingfibre masses with at least one press-roll arrangement for pressing thefibre masses and with a conveying means for conveying the fibre massesthrough the pressing mill, a press-roll arrangement according to one ofthe above described embodiments being used.

In a pressing mill with several press-roll arrangements successivelyarranged in the conveying direction of the fibre mass, the press-rollcan directly follow one another.

The pressing mill and the press-roll arrangement can be operated with afibre mass of which the absolutely dry weight per surface unit isbetween 0.1 to 20 kg/m², preferably 0.1 to 10 kg/m². As fibre masses,tows or heavy, thick nonwovens can be aftertreated.

As treatment fluids, pure water, aqueous organic or inorganic solvents,aqueous or concentrated alkaline solutions or acids, bleachingchemicals, preparation means or inert gases, respectively, vapour-likemedia, heating or cooling media as well as solvent vapours can be used.

Opposite the press-roll, a further press-roll can be arranged in thepressing mill in the region of the pressing zone which serves ascounterpressure means for taking up the pressing power. This secondpress-roll can have the same design as the above described firstpress-roll. In this configuration, the fibre mass is passed between thetwo press-rolls.

As materials for the press-rolls, metals or plastics can be used thesurface of which can be rubberized, polished or ground. In order toavoid a damage of the fibres, the edges of the press-rolls andoptionally the edges of the openings and ribs arranged at thepress-rolls should be broken.

In the following, the invention is further illustrated as to itsconstruction and function with reference to embodiments.

In the drawings:

FIG. 1 shows a schematic representation of a plant for manufacturing afibre mass;

FIG. 2 shows a cross-section of a first embodiment of a press-rollarrangement according to the invention;

FIG. 3 shows a cross-section of a further development of the embodimentof FIG. 2;

FIG. 4 shows a perspective view of a second embodiment of a press-rollarrangement according to the invention;

FIG. 5 shows a cross-section of the embodiment of FIG. 4;

FIG. 6 shows a perspective view of a third embodiment of the press-rollarrangement according to the invention;

FIG. 7 shows a front view of the embodiment of FIG. 6;

FIG. 8 shows a cross-section of a fourth embodiment of a press-rollarrangement according to the invention.

First, the course of the method for manufacturing the fibre mass isdescribed with reference to FIG. 1.

In a system 1 only schematically represented in FIG. 1, an extrusionsolution 2 is prepared. To this end, in one or more mixers a suspensionof dry or wet crushed cellulose and water and/or tertiary amine oxide isformed. Employing elevated temperatures at low pressure, water isvolatilised from the suspension to such an extent that a cellulosesolution serving as an extrusion solution is formed. In a reactionvessel 1, an extrusion solution 2 is prepared. The extrusion solutioncontains cellulose, water and tertiary amine oxide, such asN-methylmorpholine-N-oxide (NMMO), as well as optionally stabilisatorsfor thermally stabilizing the cellulose and the solvent. Examples ofstabilisators are: propyl gallate or media having alkaline effects ormixtures thereof. Optionally, further additives can be contained, suchas titane dioxide, barium sulphate, graphite, carboxymethylcelluloses,polyethylene glycols, ketine, ketusane, alginic acid, polysaccharides,colorants, antibacterially acting chemicals, flame protection agentscontaining phosphor, halides or nitrogen, active carbon, carbon blacksor electroconductive carbon blacks, silicic acid as well as organicsolvents as diluting agents, etc.

The extrusion solution 2 is delivered through a line or conduit system 4via a pump 3. In the line system 4, a pressure compensation vessel 5 isarranged, which compensates pressure and/or volume flow fluctuations inthe line system 4, so that an extrusion head 6 can be continually anduniformly provided with the extrusion solution 2.

The line system 4 is provided with means to control the temperature (notshown) by which the temperature of the extrusion solution 2 taken as anexample herein can be precisely controlled, as well as with a filtrationunit (not shown). This is necessary, as the chemical and mechanicalcharacteristics of the extrusion solution greatly depend on thetemperature. Thus, the viscosity of the extrusion solution 2 is reducedas the temperature and/or the shearing rate are increased.

In the line system 4, furthermore bursting protection means areprovided, which are necessary due to the tendency of the extrusionsolution towards a spontaneous exothermic reaction. Due to the burstingprotection means, in case of a spontaneous exothermic reaction, damagesof the line system 4 and the pressure compensation vessel 5 as well asthe downstream extrusion head 6, as they can occur due to the reactionpressure, are avoided.

A spontaneous exothermic reaction in the extrusion solution 2, forexample, occurs when a certain temperature is exceeded or in case of anageing of the extrusion solution 2, particularly in dead water zones. Inorder to avoid the occurrence of dead water zones and burblings and toensure a uniform flow of the extrusion solution through the line system4, the line system 4 is formed so as to enhance flows in the overallregion through which the highly viscous extrusion solution flows.

In the extrusion head 6, the extrusion solution is distributed to aplurality of extrusion ducts 8 in the form of spinning capillaries in anozzle space 7. The spinning capillaries 8 are arranged in line, in FIG.1 perpendicularly to the plane of projection. By means of a singleextrusion head 6, thus a plurality of continuous moulded products isprepared simultaneously. Moreover, a plurality of extrusion heads 6,each forming a plurality of continuous moulded products or, in case ofthe embodiment of FIG. 1, filaments, can also be provided. In FIG. 1,only one spinning capillary 8 is shown for the sake of simplicity.

Normally, the spinning capillary has an internal diameter D of less than500 μm, for special applications, the diameter can also be less than 100μm, preferably about 50 to 70 μm.

The length L of the spinning capillary through which the extrusionsolution flows, is at least twice the internal diameter D, maximally 100to 150 times the internal diameter D.

The spinning capillary 8 is at least sectionwise surrounded by a heatingmeans 9 by which the wall temperature of the spinning capillary 8 can becontrolled. The wall temperature of the spinning capillary 8 is inoperation about 150° C. The temperature of the spinning solution is inoperation between about 80 and 130° C. The spinning capillaries 8 canalso be disposed in an arbitrary form in a carrier body, the temperatureof which is controlled from the outside, so that the hole densities inthe extrusion head 6 are high.

The heating means 9 preferably extends to the outlet 10 of the extrusionduct situated in the flow direction S. Thereby, the wall of theextrusion duct 8 is heated down to the extrusion duct opening 10.

Due to the direct or indirect heating of the extrusion duct, at theinternal wall thereof and due to the viscosity of the extrusion solutiondepending on the temperature, a heated film flow having a low viscosityas compared with the central flow is formed. Thereby, the velocityprofile of the extrusion solution within the extrusion duct 8 and theextrusion process are positively changed such that an improved loopstability and a reduced fibrillation tendency of the extruded spinningsolution are achieved.

In the extrusion duct 8, the extrusion solution is extruded andsubsequently exits in the form of a filament 11 in an air gap 12. In theflow direction S of the extrusion solution, the air gap has a height H.

In the air gap 12, air 13 is supplied at a high velocity to theextrusion solution from the extrusion head 6. The flow direction can beguided horizontally up to the extrusion filament; the flow velocity ofthe air 13 can be higher than the extrusion velocity of the filament atwhich the continuous moulded product exits the extrusion duct opening10. Due to an air flow which is essentially guided coaxially, a tensilestress acts at the boundary surface between the continuous mouldedproduct 11 and the air 13, which stress can draw the continuous mouldedproduct 11.

After having passed the air gap 12, the continuous moulded productenters a coagulation bath zone 14 where it is wetted or moistened with acoagulation solution. The wetting can either be effected by means of aspraying or moistening device (not shown) or by immersing the continuousmoulded product 11 in the coagulation bath. Due to the coagulation bathsolution, the extrusion solution is stabilized.

A further possibility is to deposit the continuous moulded product 11essentially without tensile stresses downstream of the coagulation bathzone 14 on a conveyor means 15. The conveyor means 15 is equipped as avibrating conveyor. Due to the to-and-fro movement of the vibratingconveyor 16, the continuous filaments are deposited on the conveyormeans in straightened staples 17. Due to the conveyance on the conveyormeans 15 without tensile stresses, the continuous moulded product 11 canstabilize without detrimental effects acting on the mechanicalcharacteristics of the continuous moulded product 11, as they can, forexample, occur by a premature mechanical load shortly after theextrusion of the continuous moulded product 11.

Depending on the design, the continuous moulded product 11 is drawn offby means of a draw-off work 18 upstream or downstream of the conveyormeans 15 and supplied to a cutting machine 20 via deflection or conveyormeans 19. Via the draw-off work 18, the corresponding fibre parameters,such as titer, stability and stretching, are regulated.

The continuous moulded products 11 only of a part of the extrusion heads6 or of all extrusion heads 6 are introduced into the cutting machine 20in parallel. In the cutting machine 20, there is positioned a pair ofrolls (not shown) for supplying the continuous moulded product bundles11 of the various extrusion heads 6 to the cutting apparatus, the actualcutting apparatus (not shown) and a staple fibre washing-down device.The cutting apparatus (not shown) draws the tow fed by the pair ofdraw-off rolls by means of a water jet injector to horizontally rotatingcutting knives.

By means of the cutting knives, the fibre mass is cut to a predeterminedlength. The cutting knives maintain their edge retention during thecutting process by a continuous regrinding. By the water jet supply, afirst dissolution of the staple fibre stacks formed during the cuttingprocess is effected before the suspension of the staple fibre stacks toform a fibre mass.

An essentially mat-like fibre mass 21 exits from the cutting machine 21,which mass, together with the water supplied during the cuttingoperation, is washed into a device 22 for treating the fibre mass 21.The fibre mass 21 is formed by a random orientation of the fibres cut inthe cutting machine 20.

The device 22 for treating the fibre mass 21 essentially constitutes thesubject matter of the present invention.

In the device 22, treatment steps typical of viscose fibres areaccomplished, such as deacidification, desulphurization, washing,bleaching and washing, antichlorine treatment, washing with water aswell as applying an avivage/fat coating or other chemicals. Theindividual treatment steps or phases, respectively, each take place intreatment zones 23, 24, 25, 26, 27, which are separated from one anotherby press-roll arrangements 28, 29, 30, 31, 32, 33. In each treatmentzone 23 to 27, via an impregnation means 34, 35, 36, 37, 38 a treatmentfluid each associated to this treatment zone or treatment step,respectively, is fed from corresponding reservoirs 39, 40, 41, 42, 43.The treatment zones have a distance of at least about 0.5 m from rollcenter to roll center in the conveying direction of the fibre masses,however, the distance can be up to 10 m and more depending on therequirement of the treatment operation. In an extreme case, theindividual press-roll arrangements 28, 29, 30, 31, 32, 33 can, however,also directly follow one another, so that the press-rolls just do notcontact.

In the process, the reservoirs 39 to 43 are provided with treatmentfluid in a reverse flow, i.e. the treatment fluid from a consecutivestep in the conveying direction B of the fibre mass 21 is fed to anupstream treatment step in the treatment direction essentially withoutbeing cleaned; the direction of the flow of the treatment fluid throughthe device 22 is opposite to the conveying direction of the fibre mass21 through the device 22. In the conveying direction B, consequently thepurity of the treatment fluid in the reservoirs 39 to 43, which aredisposed as collecting vessel below the fibre mass 21, is increased. Thefibre mass 21 is conveyed by the device 22 on a conveyor means 44 whichcan be designed as endless travelling screen or an endless wire-clothbelt, an oscillating conveyor or an eccentric notched conveyor.

The press-roll arrangements 28 to 33 can be designed either, as shown inFIG. 1, as paired rolls or as individual rolls with a fixedcounterpressure face. The force of the pressure of the rolls can begenerated electrically, hydraulically or pneumatically as well asmechanically, for example by means of leverages. The typical force ofpressure of the press-roll is up to approximately 100 N per mm of theroll width.

Due to the pressing power exerted by the press-roll arrangements 28 to33, the treatment fluid introduced into the respective treatment zone 23to 27 is pressed out of the fibre mass and the treatment fluid isprevented from being carried away from a previous treatment step to thenext treatment step.

After having passed the device 22, the fibre mass 21 can be fed tofurther treatment steps not shown in FIG. 1. For example, a dryingdevice with opening aggregates for dehumidifying and relaxing the fibremass and consecutively a packaging aggregate for manufacturing a productready for shipping can follow.

FIG. 1 shows an example of the preparation of a fibre mass from aspinning solution containing cellulose. However, the use of the device22 is not restricted to cellulose fibres but can be also used fornonwoven-like or woven fibre masses of filaments of other compositions.For preparing such fibre masses of non-viscous or non-cellulosic fibres,other manufacturing methods are known from the prior art.

In the following, one press-roll arrangement each is described by way ofexample. As the basic function of the press-roll arrangements 28 to 33is the same in each case, in the following description only one singlepress-roll arrangement is discussed by way of example.

FIG. 2 shows a first embodiment of a press-roll arrangement 50 accordingto the invention for treating the fibre mass 21 in a sectionperpendicular to the moving direction B of the fibre mass 21.

The press-roll arrangement shown in FIG. 2 is used for washing the towor the staple fibres with low speeds and large fibre masses, the fibremass being moved at a speed of approximately 40 m/min in the conveyingdirection. This speed corresponds to the extrusion rate of thecontinuous moulded products at the extrusion head. With a basis weightof the fibre mass of 0.1 kg/m² when absolutely dry, the fibrethrough-put is approx. 52 kg/(m²h), the treatment fluid being fed at aflow rate of 125 m³/(h m) per m of the roll width.

The press-roll arrangement 50 comprises a press-roll 51 which isrotatably mounted in a bearing not shown in FIG. 2 and rotates alongwith the motion of the fibre mass 21 in the direction of the arrow P.The press-roll 51 is pressed into the fibre mass 21 with a force ofpressure F. In the process, a pressing surface area 52 which is theidealized enveloping surface about the press-roll 51 by which thepressing power generated by the force of pressure F acts on the fibremass 21, is formed.

The region across which the force of pressure F acts as pressing poweron the fibre mass 21 via the pressing surface area 52 is designated aspressing zone 53. In the moving direction B of the fibre mass 21, in thepressing zone first of all the pressing power is increased up toapproximatley the region where the press-roll 51 maximally penetratesthe fibre mass 21. The region of the pressing power increasing in themoving direction B of the fibre mass is hereinafter referred to ascompression region 54. Following the compression region 54 in the movingdirection B of the fibre mass 21 is an expansion region 55 where thepressing power is again reduced in the moving direction B of the fibremass.

In the compression zone 54, due to the increased pressing power thetreatment fluid 56 taken up in the fibre mass 21 is pressed out, so thatfollowing the compression zone 54 nearly no more treatment fluid 56 fromthe previous treatment step is present in the fibre mass 21.

In the embodiment of FIG. 2, the press-roll 51 is provided with passages57 which extend from the inside of the press-roll to the outside of thepress-roll. At the outer peripheral surface 59 of the press-roll 51, thepassages 57 end in recesses 58, the diameter of which is larger than thediameter of the passages 57. The passages can also be attached slit-likealong the press-roll axis and be correspondingly distributed across theperiphery.

The diameter of the bores is 3 to 12 mm with a roll diameter of 400 mm.The opening degree of the press-roll 51 is approximately 5 to 40%,largely independent of its diameter.

The through bores 57 can be distributed arbitrarily, in rows in theaxial direction or in the peripheral direction or set off relative toone another at the outer peripheral surface 59.

In the embodiment of FIG. 2, the inside of the press-roll forms a partof the impregnation means through which treatment fluid is introducedinto the fibre mass.

Inside the press-roll 51, a cover body 60 is provided, which has anessentially tubular design and comprises an opening 61 extending in theaxial direction of the press-roll 51 in the form of a slit facing thepressing zone. The cover body 60 does not move along with the press-roll51 but is stationary. At each of its ends facing the slit, the coverbody 60 is provided with sealing elements 62, so that no treatment fluidfrom the interior space 63 of the press-roll 51 can come between thecover body 60 and the internal peripheral surface 64 of the press-roll51.

The cover body 60 serves for defining the region 65 via which treatmentfluid is introduced into the fibre mass 21. The region 65 extendsaccording to FIG. 2 mainly into the region of the expansion zone 55, butalso—at least by sections—into the region of the compression zone 54. Iftreatment fluid, which can be, for example, under a pressure of 2.5 to 3bar, is conducted from the interior space 63 of the press-roll 51through the passages 57, this treatment fluid will wash out thetreatment fluid 56 from the previous treatment step in the compressionzone 54, as schematically indicated in FIG. 2, and at the same time itwill be absorbed in the expansion zone 55 by the capillary action andthe swelling of the fibre mass 21 due to the reducing pressure. As aresult, a homogenous and fast distribution of the treatment fluidsupplied through the press-roll 51 or the pressing surface area 52,respectively, is achieved. In order to be able to adjust the position ofthe slit 61 relatively to the pressing zone 53, the first cover body 60is coaxially held in the press-roll 51 to be pivoted about itslongitudinal axis X, as implied by the double arrow A.

FIG. 3 shows a further development of the embodiment of FIG. 2. Here,below only the differences to the embodiment of FIG. 2 are discussed.

The press-roll arrangement of FIG. 3 can, for example, be used forwashing a cellulose nonwoven as fibre mass 21 having a weight ofapproximately 4.1 kg/m². In this application, the fibre mass is moved inthe conveying direction at a rate of approx. 0.1 m/min. The fibrethroughput per m of the roll width is about 40 kg/(h m²) with such anapplication. The treatment fluid is supplied with a throughput of 0.7m³/(h m).

In contrast to the one-piece cover body 60 of FIG. 2, the cover body isdivided into two cover bodies 60 a and 60 b in the further developmentof FIG. 3. Each of the two cover bodies 60 a, 60 b is held independentlyof the other cover body at the inner peripheral surface 64 of thepress-roll 51 to be pivoted about the longitudinal axis thereof. Thus,in the press-roll arrangement 50 according to FIG. 3, the opening angleα as well as the orientation of the slit 61 can be changed by adjustingone of the cover bodies 60 a, 60 b or both cover bodies 60 a, 60 b. Inorder to seal the interior space 63 of the press-roll 51 outside theslit region, a sealing body 66 is provided which covers a moving slit 67which is also formed by the two cover bodies 60 a, 60 b and ensures themovability of the two cover bodies 60 a, 60 b relative to one another.The sealing body 66 can be arranged within the cover bodies 60 a, 60 bor, in an alternative embodiment, between the cover body 60 a, 60 b andthe press-roll 51. At its ends, the tubular sealing body 66 providedwith a longitudinal slit is provided with sealing elements 68 whichavoid the penetration of treatment fluid between the cover body and thesealing body.

In the embodiment of FIG. 3, due to the high variability with respect tothe size and position of the treatment zone 65, an exact adaptation tothe respective treatment step and the moistening requirements of thetreatment fluid fed into this treatment step can be effected.

In phantom lines, for example a one-sided adjustment of the left coverbody 60 b is shown in FIG. 3, resulting in a treatment zone 65 beingonly situated in the expansion region 55, through which the treatmentfluid is introduced into the fibre mass 21.

A second embodiment of a press-roll arrangement according to theinvention is represented in FIG. 4. Here, for elements the design orfunction of which essentially correspond to the elements of the previousembodiment, the same reference numerals are used.

In the embodiment of FIG. 4, the press-roll 51 is formed of a pluralityof ribs 70 extending in the axial direction X of the press-roll 51. Theribs have a wall thickness which increases in the radial direction fromthe inside of the press-roll 51 to the outside. At their outer side, theribs 70 at least by sections form the pressing surface area 52 in thepressing zone 53. The ribs 70 are each fixed at mounting plates or ringsat the two ends of the pressing surface area positioned in the axialdirection X. The ribs 70 all extend in parallel to one another and areequally spaced apart from one another, the region 71 between them isessentially free of materials. The ribs 70 can be interconnected byplate- or ring-like struts extending in the peripheral direction, sothat they obtain a higher mechanical stability.

In the embodiment represented in FIG. 4, the opening degree of thepress-roll 40 can be in individual cases up to between 90 and 95%. Thenumber of ribs is between 30 and 80, preferably about 60. With adiameter of the press-roll of 400 mm, the width of the rib can bebetween 1 and 20 mm in the peripheral direction, using broader strutsleads to a higher pressure, but a lower flow rate.

In the interior space 63 of the press-roll 51, an impregnation device 72is arranged, through which treatment fluid is guided into the interiorspace 63 of the press-roll 51. Such an impregnation means 72 can forexample alternatively also be used in the embodiment of FIG. 2 insteadof or together with the cover body 60.

Inversely, the impregnation means can also be used according to theembodiment of FIG. 2 or 3 together with the cover body 60 describedtherein.

The impregnation means 72 of the embodiment of FIG. 4 consists of acentral supply line 73 extending coaxially to the axis X of thepress-roll 51. The supply line 73 is represented in FIG. 4 cut at itsend positioned in the axial direction X, however, at its right end inFIG. 4, an end cap can be provided, or the supply line 73 can extendthrough all of the press-roll 51 in the axial direction X and supply thetreatment fluid to a further press-roll arrangement. The end of thesupply line 73 in the flow direction S of the treatment fluid can beconnected with the inlet of the supply line 73 in order to make possiblea recycling of the treatment fluid in this treatment step.

The impregnation means 72 is further provided with one or a plurality ofspray nozzles 74 which are directed to the fibre mass 21. The treatmentfluid flows from the central supply line or the collective tube 73through the individual nozzles 74 and between the ribs 70 into the fibremass 21.

FIG. 5 shows a section perpendicular to the axial direction X of theembodiment of FIG. 4.

In FIG. 5, one can see that the treatment fluid from each of the spraynozzles 74 forms an atomizing cone 75, the atomizing cones 75overlapping such that in the pressing zone 53 there is no region whichis not moistened by the treatment fluid. The atomizing cones 75 can beconical or even.

In order to prevent the treatment fluid 56 from being carried away intothe region situated downstream of the pressing zone 53 in the movingdirection B of the fibre mass 21, the height H of each rib 70 isdimensioned such that the ribs essentially situated in the pressing zone53 form a weir through which a direct flow of the treatment fluidbetween the regions at both sides of the pressing zone is not possible.

As by the rotation D of the press-roll 51 treatment fluid could beconveyed from one treatment step to the next treatment step through thespace 71 between two ribs 70, a spraying nozzle 74′ is directed to thecompression zone in order to wash out treatment fluid 56 possiblyflowing in from the previous treatment step.

Via a regulation means 76, for example by the spraying nozzles 74 beingattached to tubes 76 rotatable relative to one another and beingconcentric to the supply line 73, the treatment region 65 can beregulated with respect to size and orientation by adjusting the spraynozzles 74.

The distance between the ribs in the peripheral direction is dimensionedsuch that a sufficient amount of treatment fluid can pass between theribs and at the same time the pressing power in the pressing zone 53 canstill uniformly act on the fibre mass 21.

FIG. 6 shows a perspective view of a third embodiment of a press-rollarrangement 50 according to the invention. Here, for elements the designand function of which correspond to an element of the previousembodiments, the same reference numerals are used as in the previousembodiments.

The press-roll 51 of the embodiment of FIG. 6 comprises ribs 70 spacedapart in the axial direction X of the press-roll 51 between which aspace 71 is formed.

The press-roll arrangement 50 further comprises two impregnation means72 a, 72 b, which are arranged at both sides of the press-roll 51 withrespect to the moving direction B of the fibre mass not shown in FIG. 6for the sake of simplicity.

Each impregnation means 72 a, 72 b comprises a collective tube 73extending in parallel to the axial direction X of the press-roll 51 fromwhich supply lines 80 extend into the spaces 71 between the ribs 70 downinto the pressing zone 53.

In the embodiment of FIG. 6, the supply lines 80 of the two impregnationmeans 72 a and 72 b are interconnected in one piece, so that thetreatment fluid from the collective tube 73 of the impregnation means 72a flows to the collective tube 73 of the impregnation means 72 b and apart of the treatment fluid exits in the pressing zone 53 throughopenings of the supply lines 80 not shown in FIG. 6.

Alternatively, the supply lines 80 of the impregnation means 72 a andthe supply lines 80 of the impregnations means 72 b can be separated, sothat through the impregnation means 72 a another treatment fluid thanthrough the treatment means 72 b is introduced into the pressing zone53. This enables a higher variability and adaptability of the treatmentto be carried out by the press-roll arrangement 50 with various fibremasses and treatment fluids.

The cross-section of the supply lines 80 is designed such that itessentially corresponds to the cross-section of the spaces 71 and thuslargely fills the spaces 71. The flow S of the treatment fluid throughthe collective tube 73 is conducted through the supply lines 80 into thepressing zone 53. This can be in particular seen in FIG. 7, where afront view of the embodiment of FIG. 6 is shown in the moving directionB of the fibre mass 21.

In FIG. 7, a supply line is shown as partial section in the region ofthe pressing zone, in particular in the region of the expansion region55.

The supply line comprises openings 81 in this region, through which thetreatment fluid exits into the space 71 and enters the fibre mass 21through the pressing surface area 52.

Alternatively to the representation in FIG. 7, the section of the supplylines 80 facing the fibre mass 21 can also come into contact with thefibre mass 21. In this case, however, special arrangements with respectto the surface quality and the abrasion resistance of the supply lines80 have to be taken in order to avoid a damage of the fibre mass 21 anda premature wear of the supply lines 80 by the fibre mass 21 beingpassed under pressure.

In an alternative design of the embodiment of FIGS. 6 and 7, theimpregnation means 72 a being in front with respect to the movingdirection B of the fibre mass 21 can also be designed as a suction meansby which treatment fluid is sucked off for example from the compressionregion via the openings 81 in the supply lines 80.

In FIG. 7, furthermore a driving means 82, for example an electricmotor, is represented, by which the press-roll 51 is rotatably drivensynchronously with the motion of the fibre mass. Such a driving means 82can also be used with other embodiments. In this design, the press-rollitself can be employed as conveyor means for the fibre mass 21, by whichthe fibre mass 21 is transported through the individual treatment stepsof the pressing mill.

FIG. 8 shows a fourth embodiment of a press-roll arrangement 50according to the invention in a section in parallel to the movingdirection B of the fibre mass 21 and perpendicular to the axialdirection X of the press-roll 51. The press-roll arrangement 50according to FIG. 8 comprises a counterpressure roll 90 which is pressedinto the fibre mass 21 with a force of pressure F₂ opposite to thepress-roll's 51 force of pressure F. having the same value. Thepress-roll 51 and the counterpressure roll 90 both comprise the sameconfiguration which corresponds to the configuration of the firstembodiment as represented in FIGS. 2 and 3.

For the sake of simplicity, for the embodiment of FIG. 8 therefore forelements, the construction and function of which correspond to previousembodiments, the same reference numerals are used.

In the embodiment of FIG. 8, in the expansion region 54 the treatmentfluid is sucked off from the previous treatment step by thecounterpressure roll 90, as schematically shown by the arrow S₁, whilein the expansion region 55 treatment fluid for the next treatment stepis conducted through the press-roll 52 into the fibre mass, as indicatedby the arrow S₂.

Alternatively to this embodiment, each roll 51, 90 can effect a removalby suction as well as an impregnation in the pressing zone 53.

As represented in FIG. 1 by means of the device 22, when using thepress-roll arrangement 50 according to the invention in a pressing mill22, the press-roll arrangement for the next treatment step can directlyfollow, as due to the impregnation of the fibre mass 21 through thepressing surface area 52, an immediate homogenous distribution of thetreatment fluid in the fibre mass 21 is effected.

Thereby, the overall length of the pressing and treatment device 22 isconsiderably reduced.

Due to the immediate homogenous distribution within the fibre mass 21,which is supported by the short fibre distance in the expansion zone 55and the resulting capillary effect, the impregnation process can beaccomplished more precisely and be controlled more easily. As a result,even an impregnation with treatment fluids to be handled carefully,which possibly tend to react chemically, is possible.

The rolls according to the invention can also be employed at otherlocations of a plant for manufacturing fibres, for example as draw-offrolls with integrated waxing means.

Apart from the fibre mass of cellulose described by way of example,fibre masses of natural or synthetic fibres can also be treated by thedevice according to the invention and the method according to theinvention, for example fibre masses of viscose, acetate, polyester,polyamide and polyacryl.

Below, special examples for further illustrating the above-mentionedembodiments are given in a table.

In the examples 1 to 4 of the following table, a fibre tow manufacturedaccording to the Lyocell-method is brought into a staple shape by meansof a wet cutting machine and in this condition applied on a treatmentdevice 22 as fibre mass 21. Concerning the indications of weight, thefibre mass in an absolutely dry condition is taken as a basis. Inexample 5, the fibre tow is supplied to the treatment device 22 as fibremass 21 directly without cutting it beforehand. As treatment fluid,water is used in all examples. The device 22 is in all examples 1 to 5designed such that in every treatment zone the fibre mass 21 iscompletely penetrated by the treatment fluid across its whole thickness.Example 1 2 3 4 5 Impregnation Spraying Roll Roll Roll Roll by means ofType of roll — Condition Staple Staple Staple Staple Tow Line pres- N/mm12 12 10 10 10 sure per mm of the press- roll width Fibre mass kg/m² 7.27.2 3.1 4.1 0.1 per m² area of the treat- ment zone Washing m/min 1.51.5 0.3 0.1 36 speed Liquid m³/hm 15.4 15.4 2.5 0.7 125 throughput permetre of the roll width Fibre kg/m²h 324.8 1299.4 93.8 41.3 51.6throughput per m² of the treatment zone

In example 1, the impregnation of the fibre mass is effected accordingto the method from the prior art by spraying the treatment fluid ontothe fibre mass in the conveying direction downstream of the press-roll.In this method, the fibre mass 21 is not completely penetratedimmediately after the contact with the treatment fluid, so that thetreatment fluid accumulates like a lake above the fibre mass and onlygradually trickles through the fibre mass 21. This formation of a lakeis increased as the thickness of the fibre mass is increased. A completepenetration of the fibre mass with the treatment fluid is only achievedafter a relatively long dwell time of the fibre mass in the treatmentzone. To this end, the treatment zone has to comprise a correspondinglength in the conveying direction of the fibre mass through thetreatment device.

In example 2, the treatment is in contrast accomplished with apress-roll designed according to the invention with treatment conditionsotherwise identical to example 1. As can be seen from the table whencomparing examples 1 and 2, in example 1, i.e. the solution of the priorart, the fibre throughput per m² of the treatment zone and per hour isconsiderably lower than in example 2.

In the examples 3 to 5, the press-rolls according to the invention arealso used, so that the fibre mass is immediately penetrated whencontacted by the liquid and long treatment fields for the completepenetration of the fibre mass are not necessary. Moreover, in theseembodiments an essentially more uniform and faster distribution of thetreatment fluid in the fibre mass are the consequence.

1. A method for treating a fiber mass, such as a filament composite, awoven or a nonwoven, wherein the fiber mass is conveyed through apressing mill, in which the fiber mass is pressed in at least onepressing zone through the pressing surface area of at least onepress-roll by means of a pressing power acting on the fiber mass and thepressed fiber mass is impregnated with a treatment fluid, the fiber massin the pressing zone being conveyed through an expansion region wherethe pressing power is reduced in the passing direction (B) of the fibermass, wherein the treatment fluid in the expansion region is conductedthrough the pressing surface area into the fiber mass.
 2. The methodaccording to claim 1, wherein the fiber mass is conveyed before theexpansion region through a compression region of the pressing zone, inwhich the pressing power is increased in the passing direction (B) ofthe fiber mass and an already present treatment fluid is pressed out ofthe fiber mass (21).
 3. The method according to claim 2, wherein thepressed out treatment fluid is let off in the compression region throughthe pressing surface area.
 4. The method according to claim 1, whereinthe treatment fluid is pressed into the fiber mass in the compressionregion.
 5. The method according to claim 4, wherein the treatment fluidis conveyed through the pressing surface area into the fiber mass in thecompression region.
 6. The method according to claim 1, wherein thefiber mass is passed between at least two press-rolls in the pressingzone.
 7. The method according to claim 1, wherein the treatment fluid ispressed into the fiber mass under pressure.
 8. The method according toclaim 1, wherein before the pressing mill the fiber mass is manufacturedwith a specific weight between 0.1 and 20 kg/m2.
 9. The methodsaccording to claim 1, wherein the fiber mass is supplied to the pressingmill in the form of a mat.
 10. The method according to claim 1, whereinthe fiber mass is successively conveyed through several press-rollarrangements where in each arrangement a first treatment fluid ispressed out of the fiber mass in the compression region and the fibermass is impregnated with the second treatment fluid in the expansionregion.
 11. The method according to claim 1, wherein the fiber mass isprepared from a solution containing cellulose, water and tertiary amineoxide.
 12. The method according to claim 1, wherein the press-roll isdriven with a peripheral speed of at least 0.1 m/min. 13-18. (Canceled)19. A press-roll arrangement for treating a fiber mass moving relativelyto the press-roll arrangement, comprising at least one press-roll havinga pressing surface area through which in operation in a pressing zone apressing power action on the fiber mass is generated, and having atleast one impregnation means through which in operation a treatmentfluid is supplied to the fiber mass, wherein in operation the pressingzone forms an expansion region, in which the pressing power is reducedin the moving direction (B) of the fiber mass, wherein the press-rollarrangement comprises openings in the expansion region, through which inoperation the treatment fluid is conducted through the pressing surfacearea into the fiber mass.
 20. The press-roll arrangement according toclaim 19, wherein the impregnation means is at least by sectionsarranged within the press-roll.
 21. The press-roll arrangement accordingto claim 19, wherein the press-roll form ribs at its surface facing thefiber mass, which at least by sections form the pressing surface areaand between which in operation the treatment fluid can be introducedthrough the pressing surface area into the fiber mass.
 22. Thepress-roll arrangement according to claim 21, wherein the ribs extendessentially transversely to the moving direction of the fiber mass. 23.The press-roll arrangement according to claim 21, wherein the ribsextend essentially in the moving direction (B) of the fiber mass. 24.The press-roll arrangement according to claims 19, wherein in thepress-roll nozzles are integrated through which the treatment fluid isdirected in operation to the fiber mass.
 25. The press-roll arrangementaccording to claim 24, wherein the nozzles comprise overlappingatomizing cones.
 26. The press-roll arrangement according to claim 24,wherein the nozzles are arranged inside the press-roll and the atomisingcones are directed through the rips.
 27. The press-roll arrangementaccording to claim 19, wherein the ribs are formed as a weir which actsagainst a flow of the treatment fluid through the press-roll from thecompression region to the expansion region.
 28. The press-rollarrangement according to 19, wherein the impregnation means is providedwith a regulation means, b which the size of the region of the pressingsurface area through which the treatment fluid passes in operation, canbe regulated.
 29. The press-roll arrangement according to claim 28,wherein the regulation means is designed as a cover body disposed in thepress-roll with an opening associated to the region.
 30. The press-rollarrangement according to claim 29, wherein a regulation mimicry isprovided by which the orientation and/or size of the opening can beregulated.
 31. The press-roll arrangement according to claim 19, whereina suction means is provided through which the treatment fluid is suckedoff from the compression region in operation.
 32. The press-rollarrangement according to claim 19, wherein the impregnation meanscomprises a supply line through which the treatment fluid is conductedfrom outside the press-roll essentially into the expansion region inoperation.
 33. The press-roll arrangement according to claim 32, whereinthe supply line is arranged at least in the pressing zone at least bysections between two ribs essentially extending in the moving direction(B) of the fiber mass.
 34. The press-roll arrangement according to claim19, wherein at most about 95% of the outer peripheral surface isdesigned as passage surface for the treatment fluid.
 35. The press-rollarrangement according to claim 34, wherein at most about 90% of theouter peripheral surface is designed as passage surface for thetreatment fluid.
 36. The press-roll arrangement according to claim 35,wherein at most about 85% of the outer peripheral surface is designed aspassage surface for the treatment fluid.
 37. The press-roll arrangementaccording to wherein at least about 1% to 3% of the outer peripheralsurface is designed as passage surface for the treatment fluid.
 38. Apressing mill for treating fiber masses with at least two press-rollarrangements consecutive in a conveying direction of the fiber mass,between which at least one treatment field is formed in which atreatment fluid acts on the fiber mass, wherein the press-rollarrangement is designed according to claim
 19. 39. The pressing millaccording to claim 38, wherein at least one press-roll arrangement isformed as a conveying means by which the fiber mass is transportedthrough the pressing mill.
 40. The pressing mill according to claim 38,wherein the pressing mill comprises at least one pair of press-rollsbetween which in operation the fiber mass is passed.
 41. The pressingmill according to claim 38, wherein the fiber mass comprises inoperation a weight per surface unit of 0.1 to 20 kg/m².
 42. The pressingmill according to claim 41, wherein the fiber mass comprises inoperation a weight per surface unit of 0.1 to 10 kg/m².
 43. The pressingmill according to claim 38, wherein the throughput of the fiber mass pertreatment field is approximately 10 to 1500 kg/(m²h).
 44. The pressingmill according to claim 43, wherein the throughput of the fiber mass pertreatment field is approximately 10 to 1200 kg/(m²h).
 45. The press-rollarrangement according to claim 19, wherein the press-roll is driven at aperipheral speed of less than 400 m/min.
 46. The press-roll arrangementaccording to claim 45, wherein the press-roll is driven at a peripheralspeed of less than 60 m/min.
 47. The press-roll arrangement according toclaim 45, wherein the press-roll is driven at a peripheral speed of lessthan 10 m/min.
 48. The press-roll arrangement according to claim 19,wherein with respect to the roll width, between 0.1 and 125 m3/(h m) ofthe treatment fluid is supplied.
 49. The press-roll arrangementaccording to claim 48, wherein with respect to the roll width between0.1 and 50 m³/(h m) of the treatment fluid is supplied.
 50. Thepress-roll arrangement according to claim 48, wherein with respect tothe roll width between 0.1 and 20 m³/(h m) of the treatment is supplied.